It is important to characterize hardness of solder bumps in order to evaluate the feasibility of testing chips with non-compliant wafer test probes because they rely on compression of the solder bump to overcome non-planarity of the solder bumps. Lead free solders can be significantly harder than the lead tin solder bumps. Thus, lead free testing may require forces that are beyond the capability of existing test equipment and the structural strength of the chip dielectric layers. Also, known tools for characterizing solder bump hardness do not deform the solder ball in the same manner as the non-compliant wafer probes. Accordingly, there is no practical way to characterize the hardness of individual lead free solder bumps.
Accordingly, there exists a need in the art to overcome the deficiencies and limitations described hereinabove.